Radiation detection technology plays a significant role in health and safety applications. These applications include diagnostic systems used for medical imaging or non-destructive testing. Safety applications include systems used for mapping hot spots after nuclear accidents and for monitoring leakage of radioactive waste during storage or transportation. As the amount and availability of nuclear material increases throughout the world, the need to detect and identify dirty bombs and nuclear weapons places greater demands on the development of radiation detection technology.
The materials used in radiological weapons, such as dirty bombs, emit a significant number of gamma rays. Special nuclear materials, such as those defined by Title I of the Atomic Energy Act of 1954, emit very few gamma rays but could emit significantly more neutrons. Both gamma rays and neutrons have typical mean free distances in air on the order of 100 meters and therefore the sources of gamma rays and neutrons are detectable from a distance. However, conventional detection systems incorporate designs that focus on the detection of either gamma rays or neutrons but are not capable of detecting both types of radiation efficiently.